The Ecological Study of the Effect of Ribeiroia and Pesticides

The ecological study of the effect of Ribeiroia and pesticides on frog populations suggests that all of these statements about the study of ecology are true except that

A) it describes how organisms affect the environment.
B) it describes how the environment affects organisms.
C) it studies how biotic and abiotic factors affect each other.
D) humans are not part of its subject matter.